The Framers Made a Few Mistakes

The United States Constitution is the greatest document of governance ever written.  It was created by the wisest, most brilliant men in mankind's history.  But they, like all humans, were flawed and thus created a flawed framework of government.  Some of the errors were grammatical, some were political and some were due to living in the eighteenth century without the ability to foresee the far future.
Right from the top, in the Preamble, the word "welfare" should have been "prosperity.  But how could these responsible, self-reliant men ever dream that that one word would be so badly bastardized, so as to help create the needy, greedy welfare state that America has become.
Of course, the biggest, baddest blunder they made was allowing the continuation and perpetration of slavery in a land where personal liberty and individual rights were supposed to be paramount.  Negroid and other slaves should have been freed by the establishment of the country in 1787, rather than the execution of perhaps the most horrible war in history in 1865.  The Negroid slaves should have been given the free man's options of using their abilities and ambitions to succeed in this new country, or to repatriate to their ancestral lands in Africa.
Women should have been enfranchised from the beginning, rather than 130 or so years later through Constitutional amendment in the early 20th century.  Much like slaves, women were not much more than chattel to be used for specific purposes.   If they had been given the responsibility of the vote from the beginning, maybe they would have learned from the beginning to vote for principles like economic independence and liberty, rather than fiscal dependence and self security.
Other, more specific errors and oversights include the electoral college.  Popular election of the President should be the way the country's chief representative is selected.  Elected and appointed officers, as well as all civil employees should be held to the highest and most detailed standards of conduct, subject to the harshest penalties for the commission of any crime and the conviction thereof, which would automatically infer a conviction of breach of the public trust, resulting in the most horrendous punishments for this most heinous crime.  Officers and officials should have been specifically limited to the number and types of employers that they could employ at the government's expense.  More specificity in the way political electees and appointees are compensated is needed, to be based on their individual positive accomplishments rather than simply stating that a salary would be paid.  The Constitution should have mandated that all business of Congress is to be performed by the individual and by the committee of the whole.  Political parties should have been disallowed.   Crime should have been distinctly defined as an act of force or fraud by one party that causes demonstrable loss or harm to another party.  The freedom of religion clause of the first amendment should have been written more for the individual religious practicioner, rather than for the Church.
Those are just a few that jump to mind without so much as a glance at any of my copies of the document.  I shall add to the list as I ponder and reread.  I encourage any who read this to offer ideas on the subject. 

We, the people of the United States, in order to form a more perfect union, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare overall prosperity and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this Constitution for the United States of America.

Congress shall make no law respecting an establish of religion, or prohibiting the free exercise thereof restricting an individual from the personal and peaceable practice of any religious belief system...

A well regulated militia and a law defending citizenry being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed.